Sometimes a grudge comes up for seemingly no reason . Someone just starts to treat you differently and you have no idea what happened. You rack your brain for reasons you might have spited them and you come up empty. Did you fail to wave back at them on the street one day? Did you accidentally say something off-color at a party? Did you just happen to look at them the wrong way and now everything is different? You may never know. It's especially hard when this happens in your own family because…